Bring 4 quarts water and 1 tablespoon salt to a boil. Add egg noodles and cook according to package directions, about 7 to 8 minutes. Drain well.
Meanwhile, in a large skillet, melt 2 tablespoons butter over medium-high heat. Add the onion and cook until slightly softened, about 2 minutes. Stir in the mushrooms and cook until they begin to brown, about 2 minutes.
Add the remaining 1 tablespoon of butter, chicken, flour, paprika, 1 teaspoon salt and 1/4 teaspoon pepper. Cook until the chicken begins to brown, about 3 minutes. Add the broth and Worcestershire sauce and bring to a simmer. Cook until the sauce thickens, about 5 minutes.
Stir in the sour cream and with salt and freshly ground black pepper. Cook until the chicken is thoroughly cooked, about 2 minutes.
To serve, place egg noodles in a bowl or on a plate. Top with the chicken mixture and a dollop of sour cream if desired. Garnish with parsley.